As is well known, such a cover plate, which is usually made by press-forming, includes a base and forms one of the constituents of a clutch mechanism which constitutes a unitary assembly. Besides the cover plate, such a mechanism includes at least one pressure plate which is coupled in rotation to the cover plate, leaving the pressure plate free to move axially with respect to the latter. It also includes a diaphragm which has a Belleville ring portion and radial fingers, which bear on the base of the cover plate so as to act on the pressure plate and bias the latter away from the base of the cover plate. Such mechanisms are disclosed in U.S. patent specifications Nos.3 489 256 and 3 499 512, and the corresponding French published patent specifications FR 1 580 169A and FR 1 524 350A respectively.
In the document FR I 580 169A, the diaphragm bears, through the outer periphery of its Belleville ring portion, on a seating or engagement element which is carried by the cover plate in a junction zone of the latter, while it bears at the inner periphery of its Belleville ring portion on another engagement or seating element, commonly of divided form, which is carried by the pressure plate. In this case, the clutch is of the pull-off type in which, in order to disengage the clutch, it is necessary to exert traction, using a clutch release bearing, on the inner ends of the fingers of the diaphragm.
In the document FR I 524 350A, the diaphragm is mounted pivotally, through the inner periphery of its Belleville ring portion, on the cover plate through assembly means which mount the diaphragm pivotally on the cover plate, while the diaphragm bears, at the outer periphery of its Belleville ring portion, on a seating or engagement element of the pressure plate. The assembly means mentioned above are carried by a base of the cover plate which is integral with a junction zone by which the base is joined to an axially oriented skirt of the cover plate. In this case, the clutch is of the push-off type, which is disengaged by exerting a thrust on the inner ends of the fingers of the diaphragm by means of a clutch release bearing.
In the case where the clutch is of the push-off type, problems arise when the number of cover plates to be made is small, i.e. where not many are required over a given period of time. In this connection, cover plates are conventionally made by press-forming, and as a result, the press tooling for push-off clutch cover plates is quite expensive, i.e. not particularly cost effective, when the production quantities are low. These low quantities arise mainly from the fact that some vehicle manufacturers may desire one type of assembly means, while others want another type.